I am running Calibre 5.38 on Windows 10. I wanted to set a tweak (to change startup sorting) in Preferences->Tweak but under no circumstances would the "Apply" button activate.
Searching in the forums I noticed some old posts regarding a tweaks.py file. I rarely sign in to my machine as admin and do all my work as a non-privileged user. Since I installed Calibre for all users and learned that the tweaks were in a python file I thought this might be a permissions problem. So I logged in as administrator and ran Calibre. However logging in as admin made no difference. The "Apply" button is never active.
I then went looking for a tweaks.py file. All I found was a "default_tweaks.py" file in C:\Program Files (x86)\Calibre2\app\resources. I tried copying default_tweaks.py to a tweaks.py file
and editing the sort_columns_at_startup tweak. That caused Calibre to fail to start. So, my last ditch effort was to change the default_tweaks.py file directly (after saving a copy of course.)
I copied the tweaks.py that I created and edited file back over the default_tweaks.py in order to be sure that it wasn't a typo in the tweaks.py file that caused the failure to start. With the change directly in the default_tweaks.py Calibre is now working as I expected.
I'm certain my solution if not the recommended one
and am wondering if anyone can shed some light on my problem. In particular, what would cause the "Apply" button to always be greyed out and inactive?